SBS's Modem Pooling Service and Built-in Fax Server: Good Things Do Come in Small Packages

The proof lies in two new features of the Microsoft BackOffice Small Business Server

The saying, "Good things come in small packages," has never been more true than with the release of Microsoft BackOffice Small Business Server (SBS). This package, which marks Microsoft's entry into the small-business market, offers high performance and is easy to use. Equally important, Microsoft offers SBS at a price that small businesses can afford.

SBS is a repackaged version of the BackOffice bestsellers (such as Exchange, SQL Server, and Proxy Server) combined with an intuitive set of administrative wizards that automate most of the routine setup and administration tasks. In addition, SBS has two great new features that Microsoft doesn't offer anywhere else: a modem pooling service (which lets clients share modems for dial-up connections) and a built-in fax server. These two features are welcome additions to the BackOffice family. Unfortunately, Microsoft hasn't disclosed any plans to make them part of BackOffice for the rest of the Windows NT world.

Although SBS features automated installation, you need to know a few details about the settings that Microsoft automatically selects for you when it installs the modem pooling service and the fax server. If you haven't installed SBS yet, see the sidebar, "Choosing a Modem for SBS" (page 140), before proceeding. Using a modem that supports SBS will make your life much easier.

Modem Pooling Service If you're tired of installing analog lines and standalone modems so that your users can access dial-up services (e.g., LEXIS-NEXIS or CompuServe), you'll appreciate having SBS's dial-up modem pooling service. The modem pooling service is not only easy to use, but also easy to set up.

First, you need to verify that SBS correctly installed the modem pooling service on your server. Go to Control Panel, click the Modem Sharing icon, and click the Configuration tab. Make sure SBS has added the modem's COM port to the modem pool, as Screen 1 (page 140) shows. (You can add COM ports to or remove them from your modem pool if you need to expand or shrink it.) Although the modem pool in Screen 1 is MODEMS, your modem pool will probably have a descriptive name that matches the modem you're using. If you have more than one modem in your pool, make sure that all the modems are the same make and model. If you have a mix of modems, make separate pools for each type of modem.

Configuring the COM Port To use the modem sharing service, you need to correctly configure a COM port on your SBS client workstations.

The process is similar to the one you use to connect a modem directly to the computer: You map the route from a workstation's COM port to the modem sharing pool, install a modem driver, and associate the driver with the COM port. (You install a modem driver for the entire pool because you can't be sure which modem will be assigned to the workstation at any given time.)

Although I wish Microsoft had included COM port configuration in the automated SBS client install process, the configuration steps are straightforward. If you're on a Windows 95 client, go to Control Panel and select Programs. Select the modem sharing client, and click Add/Remove. On the Modem Sharing setup screen that appears, choose the option to Add a Modem Sharing Port and click Next. At this point, SBS will prompt you to enter the name of your server and modem pool, using the format \\servername\modempool. This format provides a map of how the COM port connects to the pool. Verify the port settings (such as baud rate and parity) by going to Control Panel and then System. Click the Device Manager tab, and expand the selection for Ports. Select the properties for your modem sharing port and make sure the necessary parameters are set.

If you're running NT Workstation 4.0 instead of Win95, the steps to configure a port are easier. Go to Control Panel, and choose Ports. Add a modem sharing port by clicking Add. When SBS prompts you for a COM port, accept the default or select the necessary port. When SBS prompts you again, enter the name of your small business server and modem pool.

If you have legacy systems running Windows for Workgroups (WFW), you can install modem sharing on them as well. Connect your WFW client to your SBS system through File Manager, and map a drive letter to the CLIENTS share if you don't already have one mapped. Open the \ms\modemshr\wfw folder, and run setup.exe. After you install the Modem Sharing Client application, launch the application and map a COM port to the modem pool. (SBS's modem pooling doesn't support Mac clients.)

Installing the Modem Driver Win95 and NT Workstation 4.0 users need to install a modem driver to complete the modem pooling service setup. When you are installing the driver, have at least one modem idle in the pool so that the modem can respond to detection.

To add a new modem to your workstation, select Control Panel and Modems and follow the prompts as if you were installing a local modem. Your system will detect and install the correct modem type, even though the modem physically resides on another computer.

At this point, your workstation will behave as if it had a local modem. You can dial up an Internet Service Provider (ISP) or another service requiring a dial-up connection. Also, you can use a HyperTerminal session to connect to a bulletin board system or host.

Although completing the modem pooling service's installation is straightforward, I found a couple of relatively minor hitches when using the service in the SBS preview copy. The first hitch concerns user names on Win95 systems. Although SBS lets you assign user names of up to 20 characters, modem sharing on Win95 fails if you have a user name longer than 15 characters. The second hitch is that modem sharing will not work if a legacy application uses interrupts to access serial ports.

The Built-in Fax Server A built-in fax server is a long-awaited feature in NT. SBS's fax server is flexible and robust. Because the fax server can handle and route both incoming and outgoing faxes, it will meet the needs of most small businesses.

Just as SBS handles the installation of the modem sharing pool, SBS handles most of the fax server's installation for you.

When you run the SBS client install process, SBS automatically configures the corresponding fax printer queue on your client (assuming you've granted your users permission to use the fax server). You just need to make a few modifications to customize how you want to use the system. Unfortunately, WFW users are out of luck here, because SBS's fax server doesn't support WFW clients. (It doesn't support Mac clients, either.)

Selecting Fax Server Options After you have run the SBS client install process, you need to set several fax server options. But first, you need to verify the state of your modem by going to Control Panel and then Fax Server. Click the Receive tab, and verify that the Fax Modem check box has a check mark.

If your fax modem doesn't support a feature called Adaptive Answer (which lets the modem distinguish between incoming fax and data calls), the Fax Modem check box will be empty. Selecting the check box will produce mixed results. The fax modem will be able to receive faxes but not Remote Access Service (RAS) calls because the server won't know which service needs to answer incoming calls. Thus, if your fax modem doesn't support Adaptive Answer, you might want to purchase another modem to split the services between the devices.

You now need to specify in Fax Server Properties how you want your server to handle incoming faxes. As Screen 2 shows, you have several options. You can send all incoming faxes to a printer (perhaps in your company's mailroom), store all faxes in a directory on your system (by default SBS will store all your faxes in %systemroot%\FaxStore), or send them to a specific inbox. If you're using Microsoft Exchange, you can also use Direct Inward Dialing (DID) information to route faxes to the appropriate people. (For your server to determine how to route faxes, your fax modem must be able to send DID information to your server. The server will compare this information against the numbers you list for your employees in Exchange's global address book and create a message from the user defined on the Routing tab of the Fax Server Properties window.)

Keep in mind that storing faxes, sending them to an inbox, and using Exchange to route faxes can quickly consume all available disk space if your company receives many faxes. I conducted an unscientific test that revealed transmitting one page of this article with 10-point text at normal resolution used about 60KB of disk space. So consider how many pages of faxes your company receives in a day before storing these files on your system. If you store faxes as image files, you might want to choose the option to have Exchange route the files to the appropriate people. Because Exchange lets you put a limit on how large each user's private message store can be, you can try to keep your free disk space from running down to nothing.

Your last task is to set your faxing preferences on your workstation by going to Control Panel and then Fax Client. As Screen 3 shows, on the General tab, you can set many general preferences, including the email address where you want delivery notifications sent. (In the SBS preview copy, however, this function was not working.) Finally, click the User Info tab and enter all your relevant contact information. Now you're ready to start faxing.

A Growing Concern I'm hooked on having the new modem pooling service and fax server as a part of BackOffice. If you work for any of the 7.8 million businesses in the US that have between 5 and 19 employees, SBS is definitely for you. My only concern is what happens to SBS companies that grow beyond SBS's 25-connections cap. If they migrate to bigger NT systems, they might be disappointed because they will have grown accustomed to the conveniences that the modem pooling service and fax server offer.

Discuss this Article 12

Devin (not verified)

on Oct 28, 2003

Remember, the client limit is 50 for SBS2k and 75 for SBS2k3....not 25 like mentioned in the article. SBS2k3's Pooling is nice, but not as easy as it seems to configure. I think this incarnation of Windows 2k3 is almost, but not quite there. The next one (prolly around 2k5) will be perfect. ^_^

I've upgraded to SBS2003, using a third party Modem Pooling solution found at http://netmodem.com. Its working very well and shares our modem pool with inbound connections from RAS and outbound connections by the netmodem clients. We are still using the Fax server which is still included with SBS2003.
James McMurry

I am interested in picking up the new SBS 2003. My main reasoning is to utilize the features you speak about in the previous version of SBS. Modem pooling and Fax server features. However when I look on Microsoft's website they do not say whether or not SBS2003 has these features. Do you know if SBS 2003 has the modem pooling option and fax server?
Aloha,

I read Douglas Toombs’ February article, “SBS’s Modem Pooling Service and Built-in Fax Server: Good Things Do Come in Small Packages.” What are the security implications of having a fax application set to answer incoming calls? A security consultant told me that apps are available on most US university sites that disable all faxing functions and let the caller browse at will after a fax application has answered the phone. He mentioned the name Crack. Any comment on this?
--Harry Goodman

The protocols used for transmitting facsimile data are completely different from those used to transfer other types of data. I believe it’s next to impossible to compromise a system’s security via an inbound fax line. You cannot influence a system via a connection of that type; the fax process will interpret every byte of data as a graphic image. I’d be very interested in any documented cases that show otherwise. Servers have other, much more vulnerable points, such as the inbound Remote Access Service (RAS) ports and any Internet connections.
--Douglas Toombs

I am also using NetModem with SBS 2003, and have found it to be considerably more robust then the modem pooling included in SBS 2000. NetModem includes support for user authentication and SSL encryption between the server and clients. NetModem also lets me control what phone numbers are allowed to be dialed, and logs all phone numbers dialed to a database. Another plus is there are no client limitations.